Bug 911786 - Part 1: Store computed relative position offsets. r=dholbert

layout/generic/StickyScrollContainer.cpp

@@ -116,11 +116,11 @@ StickyScrollContainer::ComputeStickyOffsets(nsIFrame* aFrame)
   // Store the offset
   FrameProperties props = aFrame->Properties();
   nsMargin* offsets = static_cast<nsMargin*>
-    (props.Get(nsIFrame::ComputedStickyOffsetProperty()));
+    (props.Get(nsIFrame::ComputedOffsetProperty()));
   if (offsets) {
     *offsets = computedOffsets;
   } else {
-    props.Set(nsIFrame::ComputedStickyOffsetProperty(),
+    props.Set(nsIFrame::ComputedOffsetProperty(),
               new nsMargin(computedOffsets));
   }
 }
@@ -133,7 +133,7 @@ StickyScrollContainer::ComputeStickyLimits(nsIFrame* aFrame, nsRect* aStick,
   aContain->SetRect(nscoord_MIN/2, nscoord_MIN/2, nscoord_MAX, nscoord_MAX);
 
   const nsMargin* computedOffsets = static_cast<nsMargin*>(
-    aFrame->Properties().Get(nsIFrame::ComputedStickyOffsetProperty()));
+    aFrame->Properties().Get(nsIFrame::ComputedOffsetProperty()));
   if (!computedOffsets) {
     // We haven't reflowed the scroll frame yet, so offsets haven't been
     // computed. Bail.

layout/generic/nsHTMLReflowState.cpp

@@ -831,6 +831,17 @@ nsHTMLReflowState::ComputeRelativeOffsets(uint8_t aCBDirection,
     // Computed value for 'bottom' is minus the value of 'top'
     aComputedOffsets.bottom = -aComputedOffsets.top;
   }
+
+  // Store the offset
+  FrameProperties props = aFrame->Properties();
+  nsMargin* offsets = static_cast<nsMargin*>
+    (props.Get(nsIFrame::ComputedOffsetProperty()));
+  if (offsets) {
+    *offsets = aComputedOffsets;
+  } else {
+    props.Set(nsIFrame::ComputedOffsetProperty(),
+              new nsMargin(aComputedOffsets));
+  }
 }
 
 /* static */ void

layout/generic/nsIFrame.h

@@ -927,7 +927,7 @@ public:
   NS_DECLARE_FRAME_PROPERTY(IBSplitSpecialPrevSibling, nullptr)
 
   NS_DECLARE_FRAME_PROPERTY(NormalPositionProperty, DestroyPoint)
-  NS_DECLARE_FRAME_PROPERTY(ComputedStickyOffsetProperty, DestroyMargin)
+  NS_DECLARE_FRAME_PROPERTY(ComputedOffsetProperty, DestroyMargin)
 
   NS_DECLARE_FRAME_PROPERTY(OutlineInnerRectProperty, DestroyRect)
   NS_DECLARE_FRAME_PROPERTY(PreEffectsBBoxProperty, DestroyRect)